Riviera V6-3.8L SC VIN 1 (1995)
This bulletin replaces the DTC P1406 EGR Pintle Position Error (Page 2 of 2) diagnostic chart in the Driveability and Emissions Section 6E3-A. A DTC
P1406 may be set due to an intermittently sticking EGR pintle or an open in the EGR ignition filter circuit. This condition may be intermittent. The
updated chart includes steps intended to diagnose this condition.
Also, the following statements should be added to the "Diagnostic Aids" section on the facing page.
^ Sticking EGR valve. An EGR valve which intermittently sticks partially open or closed can cause DTC P1406 to be set, especially when the
engine has reached normal operating temperatures and the EGR valve is hot. It may be possible to isolate this condition by observing "Desired
EGR Pos." and "Actual EGR Pos." on the scan tool while operating the vehicle. If a large difference in the desired and actual positions is noted,
replace the EGR valve.
